AVL DiTEST DPM 800: dynamic pressure measurement for motorsport

With many auto racing formulae now requiring engines to last many races or a whole season, the new AVL DPM 800 (DPM stands for Dynamic Pressure Measurement) is a gadget many autosport race teams will be keen to get their hands on - it's an in-cylinder pressure transducer that comprises a proprietary Piezo spark plug system with built-in pressure sensor which will enable engine tuning and the accurate gauging of wear rates and potential longevity as the season progresses. The DPM 800 will cost EUR 6550 when it is launched at the Autosport Engineering Show at NEC in Birmingham next week.

Cylinder pressure transducers have traditionally required modifications to the cylinder head of the engine on test, so have been restricted to dyno use only. Where the AVL DiTEST technology differs, is that its sensor is built into a replacement spark plug, allowing engines to be tested at the circuit, in the workshop, indeed, wherever and whenever pressure readings are needed. There is an equally effective version for compression ignition engines, in which the pressure transducer replaces the engine’s glow plug.

The other unique aspect of the technology comes courtesy of AVL DiTEST’s sister company PIEZOCRYST and concerns the sensor’s crystal that is key to the measurement process. Rather than the normal quartz type that is considerably bulkier and requires water cooling, the AVL DiTEST system utilises a Gallium Phosphate crystal. Artificially grown by PIEZOCRYST, this not only results in the smallest such sensor technology in the world, but one that can operate stably at very high temperatures without any extra cooling.

The new DPM 800 motorsport package comprises the Piezo plug, an amplifier, an oscilloscope (AVL DiTEST DiSCOPE 802) and the related software. To test the performance in a particular cylinder, one merely replaces the existing spark plug and links the Piezo plug to the rest of the AVL DiTEST equipment. Accurate pressure readings can then be taken whatever the engine temperature. Top Dead Centre (TDC) can be readily ascertained and pressure curves produced to allow optimisation of ignition timing and general performance.

Some racing formulae require engines to last a whole season without rebuild. In such situations, the AVL DiTEST system can provide an invaluable guide to general wear and tear and help predict failures before they occur – the cost savings of which could clearly be considerable.

The DPM 800 will cost EUR 6550 including plug, amplifier, oscilloscope and software, and will bring such equipment within reach of tuning companies, university test labs and the semi-professional motorsport fraternity for the first time.

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